SMS messages are short text messages that may be sent between mobile communication devices, such as cellular telephones. SMS messages may also be sent from computing devices, such as personal computers. For example, Web-based services allow computing devices to send SMS messages.
When an SMS message is sent from a user's mobile communication device, the recipient of the SMS message typically sees the source of that SMS message as the number associated with the mobile communication device. This is not the case when text messages are sent from Web-based services. The same is true for voice (VoIP—voice over Internet Protocol) messages sent from a user's computer.